thanks, pbacot -- I'm having a bit better luck now......
I'm on windows 7pro, btw. Interesting, too -- the vertical / horizontal centering tool works neat, but I've still had to nudge everthing over on the sheet or a sliver gets cut off on a standard 24x36 D sheet.

I tried something that seems to have worked. It seems like if I open the print dialog box in layout and attempt to set up a custom size, there seems to be a glitch between this and the page setup dialog box -- just won't recognize the new sheet settings. So, I closed Layout, went to the control panel printer settings, set up a D size sheet, saved settings, re-opened Layout, and it works.

Hmm...

My office is looking to purchase some pro '15 seats... for now I downloaded the free trial ot it. I've used sketchup for years, but have never done anything with Layout. Seems very cool, but I'm having some trouble getting the whole sheet to print out -- I've set up a D size sheet on my print dialog box, then went back to layout and picked the same D sheet in the page setup box. Strangely, the preview only shows a corner of the sheet, and not the whole sheet. I tested printing, and it prints what the preview shows -- only the previewed corner.
Any thoughts? I feel like I'm missing something simple...